Concrete plank production

ABSTRACT

Concrete planks are formed by moving one or more pairs of concrete extruders over a plurality of elongated plank-casting beds. The extruders are suspended from a gantry spanning and movable along the beds. The extruders are symmetrically positioned with respect to each other and the gantry whereby twisting and unbalanced load conditions are substantially eliminated. Plank lengths are simultaneously formed on beds and following their formation, the extruders are successively positioned over other beds while maintaining the symmetrical balancing of the extruders on the gantry.

United States Patent n 1 Conway CONCRETE PLANK PRODUCTION [75] Inventor: Peter J. Conway, Greenfield Park,

Quebec, Canada [73] Assignee: Grayron Industries Limited, Montreal, Quebec, Canada [22] Filed: Feb. 1, 1971 [21] Appl. No.: 111,388

[52] U.S. Cl. .425/376, 425/113, 425/447 [51] Int. Cl. ..B28b 3/20 [58] Field 01' Search ..425/213, 88, 376,

[56] References Cited UNITED STATES PATENTS 1,920,716 8/1933 Schafer ..425/111 3,217,375 11/1965 Kinnard ..425/62 3,165,807 l/l965 Berliner et al. ..425/377 X 1 1 Apr. 17, 1973 3,349,457 1 H1967 Frantz ..425/447 X Primary Examiner-J. Spencer Overholser Assistant ExaminerB. D. Tobor Attorney-Weir, Marshall, MacRae & Lamb [57] ABSTRACT Concrete planks are formed by moving one or more pairs of concrete extruders over a plurality of elongated plank-casting beds. The extruders are suspended from a gantry spanning and movable along the beds. The extruders are symmetrically positioned with respect to each other and the gantry whereby twisting and unbalanced load conditions are substantially eliminated. Plank lengths are simultaneously formed on beds and following their formation, the extruders are successively positioned over other beds while maintaining the symmetrical balancing of the extruders on the gantry.

5 Claims, 10 Drawing Figures PATENTEI] APR 1 71973 SHEET 1 BF 9 PATENTED I 71975 3,728,064

SHEET 5 0F 9 PATENTED m 3,728,064

SHEET 6 OF 9 PATENTED 3.7281364 SHEET 7 0F 9 FIG. 8.

PATENTEI] APR 1 (i975 SHEET 8 OF 9 CONCRETE PLANK PRODUCTION This invention relates to precast concrete plank production.

Precast concrete planks are in widespread use in the construction of commercial and industrial buildings. These planks are usually made with a hollow core and are produced on long casting beds on which the concrete is extruded from an extruder suspended from a moving gantry. Usually, also, the gantry spans a number of casting beds so that, when one plank length has been extruded on a bed, the extruder may be moved over another bed and the gantry actuated to move the extruder from end to end of the bed.

Since, in employing this continuous extrusion procedure, only one plank length is being cast at one time, and since the extruder must be moved from one bend to another, it (the extruder) is most frequently positioned on the gantry in offset relation to the center of gravity of the gantry. The result is unbalanced load conditions which, during operation, impose substantial strain on parts of the equipment and cause very considerable vibration of the extruder and related structure. Such vibration, in turn, adversely affects the surface appearance of the cast plank and causes variations in width and thickness thereof. Frequently, these imperfections must be removed by a subsequent surface treatment, as by grinding or the like.

The precast plank is usually formed from two or three different types of concrete mixes constituting bottom, middle, and top layers of the plank. To this end, the extruder is generally provided with two or three concrete receiving bins, one for each type of mix.

Feeding of the concrete mixes to the extruder has usually been done in the past by periodical batch supply as by means of a fork lift truck or the like.

The present invention seeks to provide a method and apparatus for producing precast concrete planks which will reduce or substantially eliminate operating vibrations by removal of twisting stresses and unbalanced load conditions and thereby result in dimensionally uniform products having an acceptable surface appearance without additional treatment. The invention also seeks to provide increased productivity and more efficient operating procedures in the manufacture of precast concrete planks.

To this end, the invention comtemplates the provision of a gantry arranged to span a plurality of plank casting beds in symmetric relation to each other with respect to a parallel center line. The gantry is adapted to carry, in suspended relation therefrom over selected beds, one or more pairs of extruders which are always maintained, under operative conditions, in balanced or symmetrically arranged positions with respect to said center line. The gantry is constructed to support the extruders in various positions thereon whereby plank lengths may be simultaneously produced on the underlying beds. A conveyor system is provided for continuous, rather than batch, feeding of concrete into the extruders.

The invention will be described with reference to the accompanying drawings, in which FIG. 1 is a schematic plan view of apparatus in accordance with the invention in operative arrangement,

FIG. 2 is a more detailed plan view of the gantry and related equipment,

FIG. 3 is a side view of the apparatus,

FIG. 4 is an end view of the apparatus,

FIG. 5 is a side view of a portion of the conveyor system,

FIG. 6 is a view, partly in section, on line 66 of FIG. 5,

FIG. 7 is a side elevation of plow means for deflecting a supply of concrete from a main supply conveyor onto extruder feeding conveyors,

FIG. 8 is an end sectional elevation of the plow means as shown in FIG. 7,

FIG. 9 is a plan view of plow means for deflecting concrete from each extruder feeding conveyor into extruder bins, and

FIG. 10 is an end elevation of the plow means shown in FIG. 9.

Referring to the drawings, the apparatus is shown as installed in a concrete plank producing plant having a plurality of elongated plank casting beds 10 on each of which a plank length 11 is adapted to be cast. It will be apparent that the planks are initially cast in relatively long lengths which are subsequently cut to required lengths. The beds 10 (as shown, 8 in number) are symmetrically positioned with respect to a parallel center line.

A gantry 12 has a pair of end frames 13 and a pair of spaced cross frames 14 connecting the end frames and spanning the beds 10 in elevated relation thereto. The gantry is mounted for movement along the beds by means of wheels 15 mounted at the base of each end frame and having rolling engagement with a parallel rail 16 on each side of the beds. Power means (not shown) are provided to drive wheels 15 and move the gantry at desired speed along the rails and beds.

The gantry 12 as suspended therefrom, in operation, a pair of extruders 17. Each extruder is of standard construction and has a pair of main bins 18.,Each extruder is suspended from wheeled frames 19 mounted on rails 20 extending from one to the other of the gantry end frames 13. Thus, each extruder is independently movable on the gantry for positioning over a selected bed 10 onto which layers of concrete are to be extruded from the extruder. Power means (not shown), may be provided for imparting movement to each extruder. As previously indicated, the extruders are always placed (when in operative position) in symmetrical relation to each other with respect to the center of gravity of the gantry and'the center line of the bed layout. To this end, the gantry has a plurality of extruder stations 21 thereon, each directly overlying one of the beds 10.

The gantry is of massive construction to provide adequate support for the extruders. Each end frame 13 (FIG. 4) includes a lower horizontal beam 22, an upper horizontal beam 23 supported by uprights 24 fixed to the lower beam 22, a pair of intermediate uprights 25 extending from lower beam 22 to a level above .upper beam 23, a beam 26 connecting the upper ends of uprights 25, braces 27 connecting the lower end portions of each upright 25 with the adjacent end portion of beam 23, cross braces 28 connecting the lower end portions-of uprights 25 with an intermediate section of beam 23, and braces 29 connecting the upper end portions of each upright 24 and each upright 25.

Each connecting frame 14 comprises a pair of beams 30 with connecting upright plates 31 which, as shown in FIG. 2, define the extruder stations 21. Each frame 14 carries a crosswalk 32 with handrail 33. A stairway 34 may be provided at each end of one of the crosswalks.

The concrete supply and conveyor system includes a first conveyor 35 which extends from floor level 36 at one end of the beds in an upwardly inclined transverse direction with respect thereto to a point adjacent a supporting wall 37 at a level spaced considerably above the uppermost level of the gantry. Conveyor 35 comprises a frame 38 and an endless belt 39 mounted on pulleys 40, the upper one of which is driven by means of a motor 41. Concrete mix is fed onto the lower end of conveyor belt 39 from any suitable supply means indicated at 42.

A second conveyor 43 is mounted on wall 37. It has a horizontal direction of travel normal to that of conveyor 35 and parallel to the beds 10. It extends substantially from end to end of the beds 10 but is laterally off set with respect to the beds and the adjacent end of gantry 12. It is also disposed at a level above the uppermost level by the gantry but below that of conveyor 35. It comprises a frame 44 and endless belt 45 mounted on pulleys 46, one of which is driven in any suitable manner. As shown in FIGS. 5 and 6 the upper end of conveyor belt 39 is disposed above the adjacent end of conveyor belt 45 and therefore is arranged to discharge concrete onto the adjacent end of conveyor belt 45.

A pair of third conveyors 46 are mounted on beams 26 of the gantry. Conveyors 46 are in parallel, coextensive relation and each has a frame 47 and endless belt 48 which travels in a direction normal to the direction of travel of conveyor belt 45. Conveyors 46 are disposed at a level below that of conveyor 43. Each conveyor belt 48 is mounted on pulleys 49, one of which is driven by means of a motor 50. Conveyors 46 are arranged above extruders 17 and extend across the tops of these extruders.

Conveyors 35, 43 and 46 are of generally similar conventional construction and include a plurality of series of rollers 51 carried by brackets 52 mounted in the respective framesv and on which the conveyor belts 39, 45, 48 are supported. It will be apparent that the rollers, as indicated in FIGS. 8 and 10, will impart a troughlike shape to the belt;

The gantry and extruders move at a substantially constant speed along the beds in order to extrude throughout the period of travel in one direction of layer of concrete on a pair of beds, such layers being of uniform thickness and width whereby the finished plank formed thereby will also be of uniform thickness and width.

The concrete mix supply and conveyor system is designed to provide av constant supply of concrete to the extruders whereby there need be little or no interruption in the operation of the gantry and extruders.

To this end plow means 53 fixed to the gantry are provided for deflecting the supply of concrete being constantly carried by conveyor belt 43 onto the two extruder supply belts 48.

Plow means 53 is more particularly shown in FIGS. 2, 4, 7 and 8 and comprises a carriage 54 fixed to the ends of conveyor frames 47 and having wheels 55 for movement on rails 56 whereby the carriage traverses the same path of travel as that of conveyor belt 43.

Mounted on the carriage 54 are a plurality of rollers 57 upon which the belt 43 is guided through the plow. It will be observed that the rollers 57 raise and flatten a section of the belt above the normal supporting rollers 51. An inclined deflecting baffle plate 58 is suspended from a carriage frame member 59 and is disposed in overlaying scraping relation to the raised belt section.

Baffle 58 is arranged to deflect concrete into a downwardly inclined trough 60 mounted on the carriage and thence into a downwardly extending bifurcated chute 61 also carried by the carriage. Adjustable gate means 62 may be provided to control flow through the two sections 63 of the chute 61. As clearly shown in FIG. 7, the outlets of sections 63 are arranged to deposit concrete onto the respective belts 48 of conveyors 46.

Plow means 64 are also provided in association with each conveyor belt 48 to deflect concrete carried thereby into the respective extruders 17. Means 64 are more particularly shown in FIGS. 2, 9, and 10.

Each means 64 comprises a frame 65 having an elongated shoe member 66 adapted to seat on rollers 51 of the conveyor. Mounted in frame 65 are a plurality of rollers 66 upon which the belt 48 is guided. Rollers 66 raise and flatten a section of the belt above the normal supporting rollers 51. An inclined deflecting baffle plate 67 is suspended from the frame and is disposed in overlying scraping relation to the raised belt section.

Each baffle 67 is arranged to deflect concrete into a downwardly inclined trough 68 mounted on frame 65 and thence into a downwardly extending bifurcated chute 69 also carried by frame 64 (FIGS. 4 and'10). As shown in FIG. 4, the outlets of section 70 of chute 69 are arranged to deposit concrete into the respective bins of each extruder 17.

It will be apparent that each plow 64 is readily manually movable into each operation position depending upon the location of the extruder. As shown in FIG. 2, the two baffles 67 are oppositely inclined for appropriate feed into the respective extruders.

Control of flow through chute sections 70 may be provided and, as shown in FIG. 10, comprises a pivotally mounted gate 71 operation of which may be controlled by means of a hydraulic cylinder 72.

The structure described lends itself readily to remote control from a single control panel of the various power-operated components.

Simultaneous production of two plank lengths, as provided by the apparatus described, not only greatly increases productivity but the resulting balanced load conditions reduces vibration to an extent that final finishing time of the planks is sharply decreased or eliminated.

The substantially automatic and continuous concrete mix supply system results in a very considerable saving of time and labor.

While the description and drawings refer to the use of only one pair of extruders on the gantry, it will be apparent that any reasonable number of pairs of extruders may be employed provided that, in operation, they are symmetrically positioned on the gantry in accordance with the invention.

I claim:

1. Concrete plank producing apparatus which comprises a gantry having end frames and a pair of spaced frames connecting said end frames and arranged to span a plurality of plank-casting beds, wheels mounted in each of said end frames for movement of said gantry thereon, a rail mounted on each of said connecting frames and extending from one to the other of said end frames, said rails being in spaced parallel relation to each other, a pair of concrete extruders each having wheels engaging said rails for suspension of said extruder therefrom and for movement of said extruder therealong, means on said connecting frames defining a plurality of extruder stations on said rails, said stations being in pairs, one of each pair for a respective one of said extruders, and each pair being symmetrically positioned with respect to the midsection of said rails, and means for moving the gantry and extruders.

2. Concrete plank producing apparatus as defined in claim 1, including a beam mounted on each said end frame in elevated relation thereto, said beams being in parallel uniplanar relation to each other and each extending in a direction substantially normal to that of said rails, a pair of concrete conveyors mounted on said beams, each said conveyor having a supporting frame and an endless belt mounted thereon in overlying relation to said extruder and extending parallel to and substantially coextensive with said rails, and concrete discharging plow means movably mounted on each of said conveyors for positioning directly above one of said extruders.

3. A concrete plank producing system which comprises a plurality of elongated parallel plank-casting beds, a pair of gantry-supporting rails substantially coextensive with and parallel to said beds, a gantry having end frames, 2 pair of spaced frames connecting said end frames and spanning said beds, wheels mounted in each of said end frames and engaging said rails for movement of said gantry therealong, means for moving said gantry along said rails, an extruder-suspending rail mounted on each of said connecting frames and extending from one to the other of said end frames, said rails being in spaced parallel relation to each other, means on said connecting frames defining a plurality of extruder stations on said extruder-suspending rails, said stations being in pairs and each pair being symmetrically positioned with respect to the midsection of said extruder-suspending rails.

4. A concrete plank producing system as defined in claim 3, including a pair of first concrete conveyors mounted on the end frames of said gantry, each said conveyor having an endless belt extending transversely of said beds, a second concrete conveyor having an endless belt extending parallel to and substantially coextensive with said beds, means carried by said gantry for feeding concrete from said second conveyor belt onto said first conveyor belts, and a third concrete conveyor having a frame extending in an upwardly inclined direction towards said second conveyor, and an endless belt on said third conveyor frame and having a lower feed end and an upper discharge end overlying one end of said second conveyor belt for discharge of concrete thereon.

5. A concrete plank producing system as defined in claim 4, including a pair of concrete extruders each having wheels engaging said extruder-suspending rails for suspension of said extruders therefrom, said extruders being movable along said rails for ositionin g at said stations, means for moving said ex ruders a ong said extruder-suspending rails, and means mounted on each of said first conveyors for discharging concrete therefrom into one of said extruders. 

1. Concrete plank producing apparatus which comprises a gantry having end frames and a pair of spaced frames connecting said end frames and arranged to span a plurality of plank-casting beds, wheels mounted in each of said end frames for movement of said gantry thereon, a rail mounted on each of said connecting frames and extending from one to the other of said end frames, said rails being in spaced parallel relation to each other, a pair of concrete extruders each having wheels engaging said rails for suspension of said extruder therefrom and for movement of said extruder therealong, means on said connecting frames defining a plurality of extruder stations on said rails, said stations being in pairs, one of each pair for a respective one of said extruders, and each pair being symmetrically positioned with respect to the midsection of said rails, and means for moving the gantry and extruders.
 2. Concrete plank producing apparatus as defined in claim 1, including a beam mounted on each said end frame in elevated relation thereto, said beams being in parallel uniplanar relation to each other and each extending in a direction substantially normal to that of said rails, a pair of concrete conveyors mounted on said beams, each said conveyor having a supporting frame and an endless belt mounted thereon in overlying relation to said extruder and extending parallel to and substantially coextensive with said rails, and concrete discharging plow means movably mounted on each of said conveyors for positioning directly above one of said extruders.
 3. A concrete plank producing system which comprises a plurality of elongated parallel plank-casting beds, a pair of gantry-supporting rails substantially coextensive with and parallel to said beds, a gantry having end frames, a pair of spaced frames connecting said end frames and spanning said beds, wheels mounted in each of said end frames and engaging said rails for movement of said gantry therealong, means for moving said gantry along said rails, an extruder-suspending rail mounted on each of said connecting frames and extending from one to the other of said end frames, said rails being in spaced parallel relation to each other, means on said connecting frames defining a plurality of extruder stations on said extruder-suspending rails, said stations being in pairs and each pair being symmetrically positioned with respect to the midsection of said extruder-suspending rails.
 4. A concrete plank producing system as defined in claim 3, including a pair of first concrete conveyors mounted on the end frames of said gantry, each said conveyor having an endless belt extending transversely of said beds, a second concrete conveyor having an endless belt extending parallel to and substantially coextensive with said beds, means carried by said gantry for feeding concrete from said second conveyor belt onto said first conveyor belts, and a third concrete conveyor having a frame extending in an upwardly inclined direction towards said second conveyor, and an endless belt on said third conveyor frame and having a lower feed end and an upper discharge end overlying one end of said second conveyor belt for discharge of concrete thereon.
 5. A concrete plank producing system as defined in claim 4, including a pair of concrete extruders each having wheels engaging said extruder-suspending rails for suspension of said extruders therefrom, said extruders being movable along said rails for positioning at said stations, means for moving said extruders along said extruder-suspending rails, and means mounted on each of said first conveyors for discharging concrete therefrom into one of said extruders. 